1. Field of the Invention
The invention is directed to a spotlight having a variable angle of radiation.
2. Description of the Related Art
Spotlights having variable angles of radiation are known, for example, from Applicant's prior patents such as U.S. Pat. No. 4,823,243, U.S. Pat. No. 6,004,007, U.S. Pat. No. 6,499,862, and U.S. Pat. No. 6,575,598. The object of the above-listed exemplary spotlights is in the technical design, wherein the emitted light intensity is as even as possible in any radiation angle position of the spotlight. With certain spotlight applications in the fields of film, television, photography, and museums, an evenly emitted light intensity is not advantageous. For example, with an application in a museum, one can normally assume that the spotlight is mounted higher than the object to be illuminated, whereby in an extreme case, the upper rim of the object is only half the distance away from the light source than the lower rim of the object. With an arrangement such as this, the light intensity on the upper rim of the object would be four times higher than on its distant end.
For the above-mentioned applications, there are conventional asymmetrical floodlights, wherein the light distribution is adjusted in the desired way by an asymmetrical construction of the reflector. Lights such as these can then also be utilized as foot ramps, for example, to illuminate backgrounds from below, and to likewise focus the asymmetrical reflector primarily on the upper end of the background. However, all of these conventional asymmetrical floodlights or foot ramps are always open-face lights without a front lens. They are also not focusable. This means that for each individual application, an asymmetrical floodlight that precisely fits the particular application must be used. Per the state of the art, if in a museum, for example, a large picture is replaced with a smaller one, a new asymmetrical floodlight, suitable to illuminate the smaller picture, must be mounted because it is not possible to focus the original floodlight, which was proper for the large picture, on the smaller surface.
Furthermore, unfavorable light distribution results have been adjusted, in many cases, with half scrims, according to the state of the art. These are wire screens having varying densities, which lower the light intensity by one-half or one aperture value (1 aperture value would be equal to half the intensity). Two of these half scrims can thereby also be placed in front of one another in order to balance the uneven illumination of the object to some degree. However, a truly perfect transition is thereby not accomplished, only a half-surface shading, that is, reduction, of the light intensity. The distant part of the object to be illuminated receives the full light intensity, whereas the parts of the object in closer proximity are subjected to an artificial reduction of light intensity. However, a continuous, even light intensity transition is not provided by the conventional half scrims.